Family plays an important yet understudied role in the development of psychopathology during childhood, particularly for children at developmental risk. Little research has examined the impact of the whole family system on the emergence of psycholopathology, even though there is emerging evidence parents may behave differently within the whole family than in the more well studied dyadic contexts. Research has begun to emerge that certain family system constructs, such as cohesion, conflict, and control may have an influence on children's development, but this research has been limited by a focus on parent-reports of family functioning, rather than utilizing observational methods. With notable exceptions, there is almost no observational research examining the unique features of families of children at developmental risk. The proposed research plan will test a complex moderated mediational model for the development of psychopathology and social competence for children during the transition to school age during which family processes play a central role. The proposed study will provide a more comprehensive understanding of family system constructs using observed systemic family interactions, longitudinal methodology, and key predictors for families with high or low developmental risk. Data for the proposed study will be drawn from a longitudinal, multi-site study examining developmental risk, family process, emotion regulation, and the emergence of child psychopathology in children. Measurement for the proposed study includes structured home observations of whole-family game tasks, naturalistic home observations of parent-child interactions, mother and father self-report data on psychological symptomatology, marital adjustment, parenting stress, and child behavior, and teacher reports of child behavior across ages five to seven. These data will allow the opportunity to longitudinally explore important public health issues related to family dynamics, as well as the antecedents and effects of family systems of children at risk during the transition to school period. PUBLIC HEALTH RELEVANCE: The proposed research has important public health implications as children with early developmental risk are three to four times more likely to develop comorbid behavior problems, and their families face increased stressors and poorer adjustment. A better understanding of the relations among family risk factors, family systems, and the emergence of psychopathology is needed to know where prevention should best intervene to prevent future difficulties.